使用版本：9.0
本人代码如下：
R = 1; L = 1; N1 = 0.1; r = 0.3; y = R/L; t = 1;
w = Sqrt[(L*c)^-1 - R^2/(4*L^2)];
A = (2*N1 + 1)*Sinh[2*r]/4;
B = 0.5*((2*N1 + 1)*Cosh[2*r] - 1);
F[k_, s_] := Exp[(k^2 + s^2)*A + B*k*s];
C1[m_, n_] := D[F[k, s], {k, m}, {s, n}] /. {k -> 0, s -> 0}
_p2[M_] := (0.5/
C1[M, M])*((-L*w)*(2*C1[M, M + 2] - 2*C1[M + 1, M + 1] -
C1[M, M]) +
0.25*(R^2)/(L*w)*(2*C1[M, M + 2] + 2*C1[M + 1, M + 1] +
C1[M, M]))*exp (-y/t);
通过检验函数C1以及之前的代码都没问题，_p2函数的定义不知道该如何修改
